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Is it possible to braze diamonds?


Frequently Asked Questions

There are two ways that make it possible to braze diamonds. The first is by plating the diamond, then brazing. The second is by using a braze containing a good carbide forming element, such as titanium, zirconium, tungsten or iron.

If the diamonds are co-plated, then most braze alloys that are metallurgically compatible with the plating can be used, although the choice of filler metal will depend on the intended application. Generic alloy systems that could be used include: Ag-Cu, bronzes, Au-, Pt- and Ni-based braze metals.

For brazing using a carbide forming element, there is no requirement for the plating of the diamonds prior to brazing. Two examples of such brazes are the Ag-Cu-Ti and Ni-Cr-B-Si alloy systems. If the Ag-Cu-Ti system is used, the Ti in the braze alloy reacts with the diamonds forming TiC that can be wetted and adhered to by the braze.

When brazing diamonds consideration needs to be given to the furnace atmosphere, as high partial pressures of oxygen will attack (oxidise) the diamonds and any carbide forming elements in the braze alloy. Typically vacuum, inert gas and hydrogen atmospheres are employed.

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